Minor Typing Improvements

can/bit_timing.py

@@ -7,7 +7,7 @@
     from can.typechecking import BitTimingDict, BitTimingFdDict
 
 
-class BitTiming(Mapping):
+class BitTiming(Mapping[str, int]):
     """Representation of a bit timing configuration for a CAN 2.0 bus.
 
     The class can be constructed in multiple ways, depending on the information
@@ -477,7 +477,7 @@ def __hash__(self) -> int:
         return tuple(self._data.values()).__hash__()
 
 
-class BitTimingFd(Mapping):
+class BitTimingFd(Mapping[str, int]):
     """Representation of a bit timing configuration for a CAN FD bus.
 
     The class can be constructed in multiple ways, depending on the information

can/bus.py

@@ -5,7 +5,7 @@
 import contextlib
 import logging
 import threading
-from abc import ABC, ABCMeta, abstractmethod
+from abc import ABC, abstractmethod
 from collections.abc import Iterator, Sequence
 from enum import Enum, auto
 from time import time
@@ -19,7 +19,6 @@
 
 from typing_extensions import Self
 
-import can
 import can.typechecking
 from can.broadcastmanager import CyclicSendTaskABC, ThreadBasedCyclicSendTask
 from can.message import Message
@@ -44,7 +43,7 @@ class CanProtocol(Enum):
     CAN_XL = auto()
 
 
-class BusABC(metaclass=ABCMeta):
+class BusABC(ABC):
     """The CAN Bus Abstract Base Class that serves as the basis
     for all concrete interfaces.
 
@@ -68,7 +67,7 @@ class BusABC(metaclass=ABCMeta):
     @abstractmethod
     def __init__(
         self,
-        channel: Optional[can.typechecking.Channel],
+        channel: can.typechecking.Channel,
         can_filters: Optional[can.typechecking.CanFilters] = None,
         **kwargs: object,
     ):
@@ -447,7 +446,6 @@ def _matches_filters(self, msg: Message) -> bool:
         for _filter in self._filters:
             # check if this filter even applies to the message
             if "extended" in _filter:
-                _filter = cast("can.typechecking.CanFilterExtended", _filter)
                 if _filter["extended"] != msg.is_extended_id:
                     continue
 
@@ -524,7 +522,7 @@ def protocol(self) -> CanProtocol:
         return self._can_protocol
 
     @staticmethod
-    def _detect_available_configs() -> list[can.typechecking.AutoDetectedConfig]:
+    def _detect_available_configs() -> Sequence[can.typechecking.AutoDetectedConfig]:
         """Detect all configurations/channels that this interface could
         currently connect with.
 

can/interface.py

@@ -7,7 +7,7 @@
 import concurrent.futures.thread
 import importlib
 import logging
-from collections.abc import Callable, Iterable
+from collections.abc import Callable, Iterable, Sequence
 from typing import Any, Optional, Union, cast
 
 from . import util
@@ -142,7 +142,7 @@ def Bus(  # noqa: N802
 def detect_available_configs(
     interfaces: Union[None, str, Iterable[str]] = None,
     timeout: float = 5.0,
-) -> list[AutoDetectedConfig]:
+) -> Sequence[AutoDetectedConfig]:
     """Detect all configurations/channels that the interfaces could
     currently connect with.
 
@@ -175,7 +175,7 @@ def detect_available_configs(
     # otherwise assume iterable of strings
 
     # Collect detection callbacks
-    callbacks: dict[str, Callable[[], list[AutoDetectedConfig]]] = {}
+    callbacks: dict[str, Callable[[], Sequence[AutoDetectedConfig]]] = {}
     for interface_keyword in interfaces:
         try:
             bus_class = _get_class_for_interface(interface_keyword)

can/interfaces/cantact.py

@@ -4,6 +4,7 @@
 
 import logging
 import time
+from collections.abc import Sequence
 from typing import Any, Optional, Union
 from unittest.mock import Mock
 
@@ -14,6 +15,7 @@
     CanInterfaceNotImplementedError,
     error_check,
 )
+from ..typechecking import AutoDetectedConfig
 from ..util import check_or_adjust_timing_clock, deprecated_args_alias
 
 logger = logging.getLogger(__name__)
@@ -31,7 +33,7 @@ class CantactBus(BusABC):
     """CANtact interface"""
 
     @staticmethod
-    def _detect_available_configs():
+    def _detect_available_configs() -> Sequence[AutoDetectedConfig]:
         try:
             interface = cantact.Interface()
         except (NameError, SystemError, AttributeError):
@@ -40,7 +42,7 @@ def _detect_available_configs():
             )
             return []
 
-        channels = []
+        channels: list[AutoDetectedConfig] = []
         for i in range(0, interface.channel_count()):
             channels.append({"interface": "cantact", "channel": f"ch:{i}"})
         return channels
@@ -121,7 +123,14 @@ def __init__(
             **kwargs,
         )
 
-    def _recv_internal(self, timeout):
+    def _recv_internal(
+        self, timeout: Optional[float]
+    ) -> tuple[Optional[Message], bool]:
+        if timeout is None:
+            raise TypeError(
+                f"{self.__class__.__name__} expects a numeric `timeout` value."
+            )
+
         with error_check("Cannot receive message"):
             frame = self.interface.recv(int(timeout * 1000))
         if frame is None:
@@ -140,7 +149,7 @@ def _recv_internal(self, timeout):
         )
         return msg, False
 
-    def send(self, msg, timeout=None):
+    def send(self, msg: Message, timeout: Optional[float] = None) -> None:
         with error_check("Cannot send message"):
             self.interface.send(
                 self.channel,
@@ -151,13 +160,13 @@ def send(self, msg, timeout=None):
                 msg.data,
             )
 
-    def shutdown(self):
+    def shutdown(self) -> None:
         super().shutdown()
         with error_check("Cannot shutdown interface"):
             self.interface.stop()
 
 
-def mock_recv(timeout):
+def mock_recv(timeout: int) -> Optional[dict[str, Any]]:
     if timeout > 0:
         return {
             "id": 0x123,

can/interfaces/ixxat/canlib.py

@@ -9,7 +9,6 @@
     CyclicSendTaskABC,
     Message,
 )
-from can.typechecking import AutoDetectedConfig
 
 
 class IXXATBus(BusABC):
@@ -175,5 +174,5 @@ def state(self) -> BusState:
         return self.bus.state
 
     @staticmethod
-    def _detect_available_configs() -> list[AutoDetectedConfig]:
+    def _detect_available_configs() -> Sequence[vcinpl.AutoDetectedIxxatConfig]:
         return vcinpl._detect_available_configs()

can/interfaces/ixxat/canlib_vcinpl.py

@@ -976,8 +976,8 @@ def get_ixxat_hwids():
     return hwids
 
 
-def _detect_available_configs() -> list[AutoDetectedConfig]:
-    config_list = []  # list in wich to store the resulting bus kwargs
+def _detect_available_configs() -> Sequence["AutoDetectedIxxatConfig"]:
+    config_list = []  # list in which to store the resulting bus kwargs
 
     # used to detect HWID
     device_handle = HANDLE()
@@ -1026,3 +1026,7 @@ def _detect_available_configs() -> list[AutoDetectedConfig]:
         pass  # _canlib is None in the CI tests -> return a blank list
 
     return config_list
+
+
+class AutoDetectedIxxatConfig(AutoDetectedConfig):
+    unique_hardware_id: int

can/interfaces/serial/serial_can.py

@@ -10,7 +10,8 @@
 import io
 import logging
 import struct
-from typing import Any, Optional
+from collections.abc import Sequence
+from typing import Any, Optional, cast
 
 from can import (
     BusABC,
@@ -26,21 +27,14 @@
 logger = logging.getLogger("can.serial")
 
 try:
-    import serial
+    import serial.tools.list_ports
 except ImportError:
     logger.warning(
         "You won't be able to use the serial can backend without "
-        "the serial module installed!"
+        "the `pyserial` package installed!"
     )
     serial = None
 
-try:
-    from serial.tools.list_ports import comports as list_comports
-except ImportError:
-    # If unavailable on some platform, just return nothing
-    def list_comports() -> list[Any]:
-        return []
-
 
 CAN_ERR_FLAG = 0x20000000
 CAN_RTR_FLAG = 0x40000000
@@ -63,8 +57,7 @@ def __init__(
         baudrate: int = 115200,
         timeout: float = 0.1,
         rtscts: bool = False,
-        *args,
-        **kwargs,
+        **kwargs: Any,
     ) -> None:
         """
         :param channel:
@@ -107,7 +100,7 @@ def __init__(
                 "could not create the serial device"
             ) from error
 
-        super().__init__(channel, *args, **kwargs)
+        super().__init__(channel, **kwargs)
 
     def shutdown(self) -> None:
         """
@@ -232,7 +225,7 @@ def _recv_internal(
 
     def fileno(self) -> int:
         try:
-            return self._ser.fileno()
+            return cast("int", self._ser.fileno())
         except io.UnsupportedOperation:
             raise NotImplementedError(
                 "fileno is not implemented using current CAN bus on this platform"
@@ -241,7 +234,11 @@ def fileno(self) -> int:
             raise CanOperationError("Cannot fetch fileno") from exception
 
     @staticmethod
-    def _detect_available_configs() -> list[AutoDetectedConfig]:
-        return [
-            {"interface": "serial", "channel": port.device} for port in list_comports()
-        ]
+    def _detect_available_configs() -> Sequence[AutoDetectedConfig]:
+        configs: list[AutoDetectedConfig] = []
+        if serial is None:
+            return configs
+
+        for port in serial.tools.list_ports.comports():
+            configs.append({"interface": "serial", "channel": port.device})
+        return configs

can/interfaces/socketcan/utils.py

@@ -9,7 +9,7 @@
 import struct
 import subprocess
 import sys
-from typing import Optional, cast
+from typing import Optional
 
 from can import typechecking
 from can.interfaces.socketcan.constants import CAN_EFF_FLAG
@@ -28,7 +28,6 @@ def pack_filters(can_filters: Optional[typechecking.CanFilters] = None) -> bytes
         can_id = can_filter["can_id"]
         can_mask = can_filter["can_mask"]
         if "extended" in can_filter:
-            can_filter = cast("typechecking.CanFilterExtended", can_filter)
             # Match on either 11-bit OR 29-bit messages instead of both
             can_mask |= CAN_EFF_FLAG
             if can_filter["extended"]:

can/interfaces/udp_multicast/bus.py

@@ -6,10 +6,10 @@
 import struct
 import time
 import warnings
-from typing import Optional, Union
+from typing import Any, Optional, Union
 
 import can
-from can import BusABC, CanProtocol
+from can import BusABC, CanProtocol, Message
 from can.typechecking import AutoDetectedConfig
 
 from .utils import is_msgpack_installed, pack_message, unpack_message
@@ -98,7 +98,7 @@ def __init__(
         hop_limit: int = 1,
         receive_own_messages: bool = False,
         fd: bool = True,
-        **kwargs,
+        **kwargs: Any,
     ) -> None:
         is_msgpack_installed()
 
@@ -126,7 +126,9 @@ def is_fd(self) -> bool:
         )
         return self._can_protocol is CanProtocol.CAN_FD
 
-    def _recv_internal(self, timeout: Optional[float]):
+    def _recv_internal(
+        self, timeout: Optional[float]
+    ) -> tuple[Optional[Message], bool]:
         result = self._multicast.recv(timeout)
         if not result:
             return None, False
@@ -204,7 +206,7 @@ def __init__(
 
         # Look up multicast group address in name server and find out IP version of the first suitable target
         # and then get the address family of it (socket.AF_INET or socket.AF_INET6)
-        connection_candidates = socket.getaddrinfo(  # type: ignore
+        connection_candidates = socket.getaddrinfo(
             group, self.port, type=socket.SOCK_DGRAM
         )
         sock = None

can/interfaces/udp_multicast/utils.py

@@ -2,7 +2,7 @@
 Defines common functions.
 """
 
-from typing import Any, Optional
+from typing import Any, Optional, cast
 
 from can import CanInterfaceNotImplementedError, Message
 from can.typechecking import ReadableBytesLike
@@ -51,7 +51,7 @@ def pack_message(message: Message) -> bytes:
         "bitrate_switch": message.bitrate_switch,
         "error_state_indicator": message.error_state_indicator,
     }
-    return msgpack.packb(as_dict, use_bin_type=True)
+    return cast("bytes", msgpack.packb(as_dict, use_bin_type=True))
 
 
 def unpack_message(